Differential brake



(No Model.)

A. PALKENAU.

- 2 Shts-Sheet 1.

DIFFERENTIAL BRAKE. No. 523,771. Patented Jan. 30, 1894.

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UNITED STATES PATENT rrrcE.

ARTHUR FALKENAU, OF PHILADELPHIA, PENNSYLVANIA.

DIFFERENTIAL BRAKE.

SPECIFICATION forming part of Letters Patent No. 513,771, dated January 30, 189 4.

Application filed August 22, 1892.

To all whom it may concern:

Be it known that I, ARTHUR FALKENAU, a citizen of the United States, residing in the city and county of Philadelphia,in the State of Pennsylvania, have invented certain new and useful Improvements in Differential Brakes, of which the following is a specification.

My invention relates particularly to structures and applications of What are known as difierential brake bands, which, as is well understood, are bands of flexible material applied around the peripheries of disks or other cylindrical or circular bodies and which, as applied, are adapted either to have movement with relation to fixed disks, or to be themselves fixed while the disks are adapted to have rotary movement,and in which, moreover,in order that the movement of that member (be it disk or band) which is adapted to have movement, may in one direction be free, and in the other be automatically prevented or stopped,the band is arranged with its respective extremities occupying points at dissimilar distances from the fulcrum of a lever to which said extremitiesare attached, in order that, said band having normallya fric tional clasp upon said disk, movement of the movable member will occasion the tilting of the lever upon its fulcrum and the carrying of that extremity of the band which is farthest from said fulcrum a lateral distance greater than the distance the other extremity is carried,--with the result, according to the direction of the movement, either of in 'effect shortening the band and occasioning its locking fast upon the disk, or of lengthening the band and occasioning the relaxation of its clasp upon said disk.

It has in practice been found to be a matter of difficulty to control the release of differential friction bands; and where, for instance, a-Weighty object is suspended from a Windlass controlled by a brake of this character and it is desired to gradually lower the object by the release of the brake, there have heretofore been no satisfactory means of definitely and regularly controlling the rate of descent, and, although it has, of course, been possible to open the band through the intervention of a lever and to immediately thereafter allow it to. be closed by its own auto- Serial No. 443,827. (No model.)

matic action, yet during this period a considerable swift descent has taken place and terminated upon the gripping of the brake, with a jar subjecting all the parts involved to undue strain.

My invention is especially applicable in connection with a hoisting apparatus, and it is its object to provide in connection with means wherebya differential brake band applied to a hoisting drum may be caused to act automatically to check the backward rotation of the drum at any time when the action of hoisting is discontinued, mechanism by which the hoisting drum may be rotated for unwinding at any desired speed, and by the action of the brake be automatically locked whenever the action of unwinding is discontinued. In other words, it is the object of my invention to provide means by which a difierential friction brake band may be utilized to regulate the speed of movement of mechanical devices in connection with which it is employed, in addition to its function of at will locking them against movement.

In the drawings I show and herein I describe a good form of a convenient embodiment of my invention organized as a hoisting apparatus, the particular subject-matter claimed as novel being hereinafter definitely set forth.

In the drawings, Figure 1 is a top plan View of a hoisting apparatus embodyinglmy invention. Figs. 2 and 3 are end elevational views of the same, sight being respectively taken from the opposite ends of the apparatus. Fig. 4 is a vertical sectional elevation taken on the line .roc of Fig. 1.

Similar letters of reference indicate corresponding parts.

In the drawings, a a are the supporting timbers of a crane or elevated structure of any character upon which are mounted castings a forming bearings for an unwinding shaft A.

B is a Windlass mounted upon and free for rotation with respect to said shaft as an axis, and conveniently provided with a series of teeth b formed, preferably, upon the periph-V cry of one of its ends b.

B is a driving shaft journaled in a bearing 19*, and provided with a spur pinion b engaged with the teeth b upon thewindlass C is a rope or cable wound upon the windlass to which is attached a load O D is what I term the brake disk of the machine, the same conveniently consisting of a casting of appropriate dimensions, having a plane peripheral surface, and being conveniently formed as a circular laterally extending flange projecting from a back plate by which it may be secured in any convenient manner to a timber or or other point of stationary support. E is a flexible friction band circumscribing said brake disk, the respective extremities of which are, as eyes, respectively engaged with studs or pivot pins f, g, projecting from a lever H pivotally mounted by means of a fulcrum pin 7? upon a lug or radialextension i of the adjacent end plate J of the Windlass drum.

M is a stud secured to the Windlass drum, which stud serves to limit the opening movement of the lever 11.

In the embodiment of my invention herein set forth, K is a trip, which constitutes a rotatable controllable releasing mechanism conveniently mounted and applied by being formed integral with a collar K itself mounted and keyed upon the shaft A at a point in line with the lever H. The trip referred to consists simply of a projecting lug or finger of any character. The lever H, in the embodiment shown, is of such length and so disposed that its inner end exists normally just in front of the trip and in line to be encountered by it. v

The operation of the apparatus set forth may be described as follows: Rotation of the driving shaft B to the left, Figs. 1 and 2, will occasion the rotation of the Windlass drum B to the right, and the winding of the rope thereupon to occasion the elevation of the load O In this rotation of the Windlass, the lever II and friction band are revolved with or carried by it, the friction band in its travel slipping easily around the brake disk for the reason that the direction of movement of the band Windlass and its lever is such as to occasion the opening of the band upon the stationary brake disk. In any reverse rotation of the Windlass drum, that is to say rotation in the proper direction to effect the unwinding of the rope 0 (whether occasioned by the rotation of the shaft 13 to the right in Fig. 1, or by the initial pull of the load itself), the lever and the friction band tend to participate. Inasmuch, however, as in such last mentioned rotation of the drum lever and band, the friction exerted upon the band by the stationary disk in the advance movement of the drum and lever,

operates to shorten or close the band, said band is instantly locked upon the disk, and of course secures the windlass against the continuance of such rotation. The unwinding shaft A, however, is rotatable independently of the Windlass, and, being rotated, its trip is carried into contactwith the lever, and slightly deflects it, with the result of occasioning the lengthening or opening of the band. Under the actuation of the weight the Windlass immediately rotates, and again in such rotation and during the dwell of the shaft, immediately locks the band fast upon the disk. Further rotation of the shaft again trips the lever and relaxes the band, and further rotation of the freed Windlass again locks the band, and so on, untilthe required descent of the load or the required movement of the Windlass or other mechanism employed is accomplished.

The end of the shaft A is, as shown in Fig. 1, many-sided, and anysuitable hand or power actuated crank, or other motive instrumentality, may be applied to it.

For convenience of description I have referred to the rotations of the Windlass and shaft A as though they were intermittent, and the alternate locking and unlocking of the band as though distinct stops and starts were made at each operation; in practice, however, the shaft A is preferably given a continuous rotation in which its trip constantly drives the lever II in front of it so that the lowering of the load is practically continuous and uninterrupted. The movement of the lever itself, as it is carried around the shaft A, may be described as an oscillatory movement upon an axis about midway of its length,-its outer end being first slightly advanced by the rotation of the Windlass and stopped by the locking of the parts, and the inner end being in turn slightly advanced by the encounter of the trip.

When it is desired to rotate the Windlass to lower the rope at times when no load is attached to the latter, the shaft A is rotated to, through its trip, carry the lever H against the stud M, both of which latter are connected to the wind1ass,-so that further rotation of the shaft and trip will (the friction band being open) occasion the desired rotation of the Windlass.

It will be understood that the invention disclosed by which a regulated release of a differential friction band is accomplished, may be applied to a great variety of uses and embodied in a multiplicity of forms, and that the embodiment and the application herein set forth are to be understood as typifying and not as exhausting its possibilities of embodiment and application.

Having thus described my invention, I claim-- 1. In combination with a differential friction band mechanism, consisting of two members, namely, a disk and a lever-provided band circumscribing the same, one of which members is stationary and the other member of which is engaged with ahoisting drum and is free to rotate in one direction while its slight movement in the opposite direction effects the shortening of the band and the locking of the parts,a hoisting drum,-'-rotat* able controllable releasing mechanism the rotation of which continued in one and the same direction. occasions the release of the band each time the latter is shortened or closed in the movement of the movable member in said opposite direction under the pull of a load acting on the drum,-substantially as set forth.

2. In combination with a differential friction band mechanism, consisting of two members, namely, a disk and a friction band circumscribing the same, a lever to which the ends of said band are attached, one of which members is stationary and the other member of which is engaged with a hoisting drum and is rotatable, and the rotation of which in one direction throws said lever so as to lengthen or open the friction band while its slight rotation in the opposite direction throws said lever so as to shorten or close the same, ahoisting drum, a trip adapted to be rotated completely around its axis, and in its continued rotation to encounter and occasion the throw of the lever and the lengthening or opening of the band each time the latter is shortened or closed by the movement of the movable member in said opposite direction under the pull of a load depending from the hoisting drum, substantially as set forth.

3. In combination with a differential friction band mechanism consisting-of two members, namely, a disk and a band circumscribing the same, the ends of which band are attached to a lever, one of which members is stationary and the other member of which is engaged with a hoisting drum and is rotatable, and rotation of which in one direction throws said lever so as to lengthen or open the friction band while its slight rotation in the opposite direction throws said lever so as to shorten or close the same,-said lever,-and a hoisting drum,as a means for regulating the rotation of said movable member in said opposite direction a trip adapted to be rotated and which in its continued rotation in one and the same direction operates to throw the lever to bring the band to its lengthened or open position after each of the rapidly-recurring shortenin gs or closings of said band occasioned o by the movement in said opposite direction of the movable member under the pull of the load, substantially as set forth.

4. In combination with a diderential friction band mechanism consisting of two members, namely, a stationary disk and a band circumscribingthe same, the ends of which band are attached to a lever, a lever, the movable member of which mechanism when turning in one direction throws said lever so as to lengthen or open the friction band while a slight rotation of said member in the opposite direction throws the said lever so as to shorten or close the friction band,-a rotatable device upon which the said lever is pivotally mounted-=-and a trip mounted on a rotatable device, and adapted to follow the lever and to throw it to occasion the lengthening or opening of the band each time said band becomes shortened or closed in the movement of said'movable member in said opposite direction,substantially as set forth.

5. A rotatable body provided with a friction band circumscribing a stationary brake disk, a stationary brake disk, a lever carried by said rotatable body to which said band is attached, and a trip provided with means such as a rotatable shaft to occasion its rotation so as to carry it against said lever,-substantially as set forth.

6. In combination, the rotatable shaft A, the Windlass B mounted free for rotation upon said shaft, means for occasioning the rotation of said Windlass to elevate a load attached to it, the lever H, the friction band E, the disk D, and the trip K upon the shaft, substantially as set forth.

7. In combination, the rotatable shaft A, the Windlass B, mounted free for rotation upon said shaft, means for occasioning the rotation of said Windlass to elevate a load attached to it, the lever H, the friction band E, the disk 

